Temperature regulation for cargo carriers and the like



Jan. 2, 1962 P. K. BEEMER ETAL 3,

TEMPERATURE REGULATION FOR CARGO CARRIERS AND THE LIKE Filed Nov. 21, 1958 5 Sheets-Sheet 1 I IGLI. 24 10 &9 J34 pl-70L. I6. flEEMEE, ciam/ W. Maze/s",

INVENTORS.

Jan. 2, 1962 P. K. BEEMER ETAL 3,015,217

TEMPERATURE REGULATION FOR CARGO CARRIERS AND THE LIKE Filed Nov. 21, 1958 3 Sheets-Sheet 2 i M 1 $8 7 M, M am i W B W K m 5 KW w M 0 .d@ if 1 4 i A 4 7 1 g x. fie Z 7 ,2 2 w W 7 E M 2 3 Sheets-Sheet 3 z rfi 43 1%5 b 11 w w W I d P. K. BEEMER ETAL TEMPERATURE REGULATION FOR CARGO CARRIERS AND THE LIKE 4 9 W a, 0/. 1,. w 4 0g .J 6 QII M 5 a 1fl|lflh. F W R l :r ,4 i 5 I W 6 w W W W. 5 w k 2 a iii: a 4 a 2 E L 1 Jan. 2, 1962 Filed Nov. 21, 1958 pl 10/ I? 5 United States Patent ()filice 3,615,217 Patented Jan. 2, 1*962 3,915,217 TEMPERATURE REGULATIGN FQR CARGO CARRIERS AND THE LIKE Paul K. Reamer, Laguna Beach, and John W. Morris,

Whittier, alif., assignors to Preco Incorporated, Los

Angeles, Calif., a corporation of Qaiifcrnia Filed Nov. 21, 1958, Ser. No. 775,630 24 Ciairns. (Cl. 62--1$6} This invention relates to transport vehicles that are refrigerated by means of heat absorbing materials such as ice.

The invention relates more particularly to apparatus for controlling the temperature within such vehicles. The invention is especially useful in connection with railway refrigerator cars. Without implying any limitation upon its scope, the invention will be described, for the sake of clarity, with particular reference to vehicles of that illustrative type.

A primary object of the present invention is to enlarge the field of usefulness of refrigerator cars and the like by providing improved temperature control whereby each individual load can be maintained uniformly at substantially any temperature that may be selected by the shipper as being particularly suitable for that load.

In the past, properly equipped refrigerator cars have been reliably effective for maintaining the relatively low temperatures required to preserve a wide variety of perishable food products. However, it is desirable to ship certain products at intermediate temperatures. For example, commodities such as potatoes may be injured by temperatures close to freezing; and if intermediate temperatures are available, commodities such as tomatoes may be caused to ripen to a selected extent during shipment. Previously available refrigerator car equipment has not been capable of holding intermediate temperatures reliably and uniformly.

The present invention overcomes that difficulty by providing a temperature control system that is remarkably simple and economical. Moreover, existing cars can conveniently be equipped with a control system in accordance wtih the invention. That system is highly reliable and economical in operation. It is typically capable of absorbing heat at a higher rate than previously available systems, especially during precooling of warm loads.

In accordance with the invention, the temperature within a refrigerator car or the like is controlled by providing at least two distinct types of air circulation and by novel control mechanism for that dual circulation. One of the two types of air circulation carries the air over a closed path which passes in series through the ice bunker, preferably in an upward direction, and through the load, preferably in a downward direction. That type of air circulation is operated under control of a temperature sensing device, such as a thermostat, which causes it to operate when the air temperature wtihin the car is higher than the desired value, and to be positively cut off when the temperature is lower than the value.

A second type of air circulation is provided along a path which passes through the load, but which by-passes the ice bunker. That by-pass circulation is preferably maintained continuously, independently of the thermostat device. Alternatively, the by-pass circulation may be operated only when the first described circulation through the ice bunker is shut ofi. For example, the air circulation may be switched between the two described types, circulation through the bunker taking place when the temperature sensing mechanism indicates too high a temperature, and by-pass' circulation taking place at other times.

In accordance with a further aspect of the invention, the temperature responsive element is mounted in position to be in continuous thermal contact with circulating air. In preferred form of the invention, the temperature sensing element is exposed to air of the: by-pass circulation only, that circulation being operated continuously.

The invention further provides by-pass circulation in a particularly convenient and effective manner via a passageway which is formed for that purpose within the bulkhead between the lading compartment and the ice bunker of the car. Such a bypass passageway is arranged to communicate at one end with the lading compartment below the floor racks and at the other end with the lading compartment above the top of the load. Air driven through such a by-pass passageway in the bulkhead by fan or blower mechanism of any suitable type produces vertical air movement through and around the load. By maintaining such by-pass circulation at times when no cooling is required, a uniform temperature distribution is maintained throughout the load and at the sensing element of the thermostat control. The latter advantage is made particularly effective by placing the sensing element directly in the by-pass passage.

A particular advantage of the described arrangement of the by-pass passage is that it does not occupy any normally useful space in the car and hence does not reduce the available lading space nor interfere with handling the load.

Particularly effective by-pass circulation is obtained by cooperating placement of bypass passages in the two bulkheads at opposite ends of the car, those passages being preferably located closely adjacent opposite side edges of the respective bulkheads. That location of the bypass passageways in the bulkheads further provides a convenient, efiective and fully protected mounting posi tion for the temperature sensing element.

A further aspect of the invention concerns particularly effective damper structure for positively controlling circulation through the ice bunker. The invention also provides a novel manner of constructing and controlling the dampers which insures efiective cooling of the load by natural convection even if the control mechanism or circulating fans should fail.

In addition, the invention provides improved baffle structure for obtaining uniform air distribution over the top of the load while permitting maximum freedom of placement of the load in the lading compartment.

A full understanding of the invention, and of its further objects and advantages, will be had from the following description of an illustrative manner of carrying it out. That description, of which the accompanying drawings form a part, is intended only as illustration, and the particulars of the described embodiment are not intended as a limitation upon the scope of the invention.

In the drawings:

FIG. 1 is a schematic perspective, partly broken away, representing one end of a typical railway refrigerator car embodying the invention;

FIG. 2 is a horizontal section through the upper portion of the car bulkhead, taken on the lines 2-2 of FIGS. 3 and 4, divided into two portions on line A-A for clarity;

FIG. 3 is a vertical section on line 33 of FIG. 2;

FIG. 4 is a vertical section on line 44 of FIG. 2;

FIG. 5 is a diagram including a fragmentary and schematic elevation in the aspect indicated by line 5-5 of FIG. 3 and a schematic wiring diagram of an illustrative control system; and

FIG. 6 is a schematic plan at reduced scale.

As shown schematically in FIG. 1, one end of a typical railway refrigerator car is represented at ltl, supported on the wheel truck 11 and having sidewalls l2, ceiling 14, and floor 16. A transverse bulkhead 22, spaced from the car end wall 18, separates the ice bunker 20 from the lading compartment 3t) of the car. ice is typically supplied to ice bunker 25) through ice hatches 24 in the roof of the car, and is supported above the level of floor 16 by one or more ice grates 26. In lading compartment Ball, a lading floor 32 is provided in spaced relation above car fioor 16. Lading floor 32 typically comprises a plurality of removable floor racks 34, composed of longitudinal joist sections 35 and spaced transverse floor boards 36. Passages 40 between the spaced joists 35 are thereby provided for air fiow longitudinally of the car below the lading floor. The apertures between floor boards 36 permit air to pass between passages 50 and the main body of lading compartment 38 above lading floor 32. Hence air can pass vertically through and around the load between passages 46 and the open chamber between the top of the load and car ceiling 14.

Bunker bulkhead 22 typically comprises transversely spaced vertical studs 44 faced with sheet material and extending between upper and lower beam members 42 and 43, respectively. The facing on the outer wall of the bulkhead, facing ice bunker 20, is indicated at 46; and the inner facing, forming an end wall of lading compartment 30, is indicated at 48. Facing 48 typically comprises a metal sheet 48a and an overlying apron of plywood 481'). The bottom edges of bulkhead facings 45 and 48 are spaced from car floor 16, typically at approximately the level of lading floor 36, as shown, for example at 47 and 49, respectively, in FIG. 3. Passages 41 are thereby formed between the bulkhead studs through which passageways 40 communicate with the lower portion of ice bunker 20. Similar air passages are typically formed at the top of bulkhead 22 between ice bunker 20 and lading compartment 30. Power driven fans or blowers may be provided in such air passages either at the top or at the bottom of the bulkhead, as described, for example in United States Patents 2,349,315 and 2,619,- 020. The natural convection of air within the car may thereby be supplemented or replaced, providing more reliable circulation of air over the ice in bunker 2t} and through the load in lading compartment 30. The present invention utilizes fan driven air circulation in combination with a variety of novel features to be described, and provides improved temperature control not obtainable in the prior art.

As illustratively shown in FIGS. 1 to 4, inner bulkhead facing 48 is cut away above a uniform height across the entire width of the bulkhead, and is replaced by a fan panel 60. The lower edge portion of panel 60 preferably overlaps the upper edge of metal facing 48a and abuts that of apron 48b. The upper and lower edges of panel 60 are turned under to form flanges 611 spaced from the panel plane, which serve to align panel 60 substantially in the plane of the exposed face of apron 43b. The upper edge of panel 60 abuts the downturned inner flange of beam member 42. Fan panel 60 may conveniently be mounted on the bulkhead by means of bolts 63, which engage flanges of the channel members 45 that typically compose studs 44.

Air is circulated by a suitable number of axial fans, which are mounted in circular apertures in panel 60 at positions intermediate adjacent studs 44- of the bulkhead. Three such fans 70, 72 and 74 are illustratively employed in the present embodiment, as shown best in FiG. 2. Each fan comprises a rotating blade assembly 77, an electrical drive motor 76 and a cylindrical housing and duct member 78, in which the motor is co-axially mounted by means of struts 79. Housing members 78 are typically welded in fitting circular apertures in panel 6th, projecting slightly from its plane on both sides. All of the fans are preferably arranged to deliver air from left to right as seen in FIGS. 2 to 4, for example.

Apertures are formed in the outer facing 45 of the bulkhead in alignment with each of the fans 72 and 74, providing passages 82 for free access for fan driven air between ice bunker 2t and lading compartment 30 of the car. Those apertures contain protective grids which are of sufficiently strong construction to protect the fans from blocks of ice in the bunker. Vertical air flow within the bulkhead between the pairs of studs adjacent fans 72 and 74 is prevented by inserting horizontal plates 84 just below the grids 80. Hence the left sides of those fans, as seen in FIGS. 2 and 3, communicate only with the interior of ice bunker 20.

Fan 7%), on the other hand, as shown best in FIGS. 2 and 4, is completely isolated from bunker 20 by the continuous outer bulkhead facing 46. The left side of fan 74), as seen in those figures, communicates with the vertical passage 85, which extends the entire height of the bulkhead between its opposing facings and between the two studs 44a and 44b that are adjacent that fan. Air flow between the lower end of vertical passage 85 and the interior of ice bunker 20 is blocked by the plate 86 (FIG. 4) which is secured to the outer side of the bulkhead studs below the lower edge 47 of outer facing 46. However, vertical passage 85 communicates freely with passageways 40, already described, below lading floor 34 in the lading compartment of the car. Air flow between passage 85 and fan 70 may be facilitated by cutting away the lower portion of fan housing 78 within the bulkhead, as indicated at 83.

All three fans communicate at their right sides, as seen in FIGS. 2 to 4, with a plenum chamber 90, which is formed between car ceiling 14-, the inner face of the bulkhead and a diagonal Wall member 92 and grid structure 94. Wall member 92 extends from substantially the lower edge of fan panel 66 diagonally upward toward car ceiling 14, with its upper edge spaced therefrom. That space is occupied by grid 94, which permits substantially free air flow between the upper portion of plenum chamber and lading compartment 30 of the car. Wall member 92, when in normal position, and grid 94 are preferably supported on brackets 96, which may be mounted directly on fan panel 6%, as indicated at 97 in FIG. 4. The lower edge of wall member 92 is preferably mounted by means of a horizontal hinge 98, and its upper portion is releasably secured to brackets 96, as by the screws 99. Release of screws 99 then permits the wall member to be swung downward against the face of apron 48b, providing convenient access for servicing fans 71 72, and 74, and their associated equipment to be described.

Plenum chamber wall 92 extends upwardly over the greater part of the diameter of fan housings 78, and therefor acts as a baflie which intercepts a direct air stream flowing from the fans toward lading compartment 36). The effect of plenum chamber 9! is therefor to moderate the direct fan blast, and to transform it into a more uniform and diffused movement of air through grid 94. The air movement is thus distributed more evenly over the entire area of the lading compartment, maintaining uniform temperature conditions throughout the body of the load. Moreover, that uniformity of air distribution is effectively provided even when the load within compartment 30 extends within a relatively short distance of car ceiling 14. In practice, the load may be built up substantially to the lower edge of grid 94 without irnpeding effective air circulation and without causing excessive concentration of that circulation upon certain portions of the load.

Fans 72 and 74 are provided with damper mechanism which effectively shuts off air circulation through passages 82 when the fans are not operating. In accordance with the present invention each of those dampers, which are indicated generally at 1% and till, comprises a fiat disk of light sheet material 102 which is adapted to overlie the inner edge of housing member 73, as shown in dot-dash lines in FIG. 3. Damper disk 1&2 is preferably mounted for swinging movement about a horizontal axis which lies below housing member 73 and between the axial ends of the housing. That pivotal axis in the present embodiment is the common axis of the two damper shafts 106 which are rotatably mounted on the face of fan panel 6@ by means of the brackets 188. Disks Hi2 are mounted on the respective shafts res by disk supporting brackets 110, formed from rods bent to V-shape with their ends welded to the shafts. Each disk is mounted by a single central screw at the vertex of its bracket illlfi. The adjacent ends of shafts 1 96 carry crank formations 114 which enter opposite sides of a bore in the fitting 115 mounted on the free end of link 116. The other end of the link is pivotally mounted on a rod 118 which comprises the output member of an electrical actuating mechanism 120. Actuator 120, which may be mounted directly on panel 60 by a strap 122, typically comprises a solenoid or motor and reduction gear mechanism of known type, and is energizable by electrical current to retract output rod 118 upwardly. That rod is yieldably biased downward, as by a spring which is indicated schematically at 121, but may form part of the actuator mechanism. Accordingly, Whenever the actuator is de-energized its output rod is returned to its normal downwardly extended position, as shown in FIGS. 3 and 5.

Whatever its detailed construction, the mechanism is so arranged that with actuator 12% de-energized both damper disks 102 are swung away from fan housings 73 to the position shown in solid lines in FIGS. 2 and 3 closely adjacent wall 92 of plenum chamber 90. In that position of dampers, free fiow of air is provided past each of the fans 72 and 74 between ice bunker 2t) and plenum chamber 5 h, and therefrom via grid 94 to lading compartment 36. Electrical energization of actuator 12% draws crank arms 114 upward, swinging the damper disks 102 to the left as seen in FIGS. 2 and 3 into engagement with the circular edge of fan housings 78, completely closing off air flow past the fans and effectively isolating the upper portion of lading compartment 343 from ice bunker 2t).

An illustrative electrical system for controlling the described air circulating fans is shown schematically in FIG. 5. Electrical power is supplied from a power source indicated schematically at 13d via a main control switch 132 to supply lines 133 and 134. Source 136 may be of any suitable type, providing either direct or alternating current power. It will be illustratively described for definiteness as a single phase alternator. if it is preferred to employ three-phase power, for example, the system to be described can be modified accordingly in known manner.

Many of the advantages of the present control system may be obtained by supplying power to alternator 13 from rotation of the car wheels, as by mechanism suc as is described, for example, in United States Patent 2,757,619, issued on August 7, i956, and entitled, Power Take Off Mechanism For Raiload Cars and the Like. However, to obtain in full the high precision and reliability of temperature control which the present system is capable of providing, it is preferred to utilize a source of electrical energy that is continuously operative from the time the car is delivered for loading until it has been unloaded at its final destination. Such continuously available power may be provided, for example, by driving alternator 130 from an internal combustion engine 133., as by a belt drive 135. The alternator and engine are preferably mounted in a suitable housing 133 below the car floor, as indicated in FIG. 1. A fuel tank 139 is provided, having sufiicient capacity for at least to 14 days of continuous engine operation.

As illustratively shown, line 133 is connected directly to one terminal of each of the electric fans '70, 72, and 74, and also to one terminal of actuator 120. Line 134 is connected via line 136 to the other terminal of fan 3 7t) and is connected to the armature 141 of a thermo statically controlled double-throw switch indicated schematically at M0. Switch armature 143i is shiftable between two electrical contacts 142 and 143i, suitable mechanism being provided to insure positive contact of the switch with one contact or the other. The mechanism is shown schematically as comprising the resilient member 145' which engages the cam member 146 of armature 141.

Contact 142 is connected via the lines 1.64 to the other terminals of fans 72 and 74. Switch contact 143 is connected via the line 162 to the other terminal of actuator 120.

Switch armature 141 is driven, as indicated by the dashed line 148, by a temperature responsive device 150 which is shown as illustratively comprising a bi-metallic element 151 mounted on a rotatable shaft 152. Shaft 152 carries an arm 154 by which its rotational position may be conveniently set and which includes a pointer that moves over an indicating scale represented generally at 155.

Temperature responsive device 156 is mounted in position to sense the air temperature within the refrigerator car. In preferred form of the invention, device 150 is responsive to the bypass air stream in vertical passage 85 within bulkhead 22, preferably at a point near the lower end of that passage. Such mounting of sensing device 159 in passage 85, within a protective cylindrical housing, is represented in FIGS. 1, 2 and 4. Shaft 152 typically extends through a bore in the end stud 44a of the bulkhead into a control housing 17%, which is set into the outer side wall of the car. Indicator and control arm 154 and scale 155 are thus conveniently accessible from outside the car by opening housing door 171 for observation or adjustment. Switch 149 may be mounted within housing 17d, and may be operatively connected to element 151 in any suitable manner. For example, the mechanical connection. indicated at 148 in FIG. 5 may comprise a sleeve coaxially surrounding shaft 152. Scale 155 typically includes a plurality of spaced reference marks 156 which correspond to predetermined temperatures within the range of temperatures which may be desired within the refrigerator car. That range, may for example, extend from 36 to 70 F. as indicated in FIG. 5. Scale 155 preferably includes also an index mark 158 which is spaced an appreciable distance beyond the low temperature end of the series of reference marks 156 and which may be designated by the word heat. Bi-metallic element 151, as illustrated, is arranged as a spiral which tends to unwind in response to decreasing temperature, such unwinding moving its operating end 157 to the left as shown in FIG. 5. Such movement shifts switch armature 14-1 from the position shown in FIG. 5, in which it engages contacts 142, into engagement with contact 143. The parts are so designed and arranged that movement of the switch occurs at a temperature closely corresponding to the'temperature value indicated on scale 155 by pointer 154. Hence, when the temperature of bi-metallic element 151 exceeds the set scale temperature armature 141 engages contact 1142; otherwise the armsture engages contact 143. The control system thus causes the fans 72 and "id to operate, circulating air through the ice bunker and cooling the entire lading compartment of the car, whenever the car temperature, as indicated by element 151, exceeds the selected value. When that car temperature is reduced to the selected value, or falls below it, switch contact 142 is opened, stopping the cooling fans. At substantially the same time, switch contact 14-3 is closed, energizing actuator 120, which closes dampers 14MB, positively preventing air circulation through the bunkers via passages 82. That control action does not, however, affect fan 7'9, which operates continuously. That continuous operation of fan 7 maintains tempera ture equilibrium throughout the lading compartment of the car when cooling fans 72 and 74 are turned off. It

performs the further important function of circulating air directly from the lading compartment over temperature responsive element 151 at all times, thus maintaining element 151 in continuous equilibrium with the ambient temperature in the lading compartment of the car.

A particular advantage of the described control system is that in normal operation dampers 100 positively cut off cooling circulation through the ice bunker when further cooling of the car is not required; and yet the dampers automatically return to open position if the control system is accidentally disabled, for example by power failure. If power failure occurs during the cooling phase of operation, while dampers lltlil are open, the only mediate efiect is to stop the fans. If power failure occurs when only the by-pass circulation is operating, dampers 1% being closed, actuator 121i is immediately de-energized. Spring 1121 then reliably opens the dampers In either case, the present control apparatus reverts automatically, during power failure, to a condition that corresponds substantially to the gravity circulation system for which most refrigerator cars were originally designed. Any serious losses from failure of the control system are therefore avoided.

In railway refrigerator cars an ice bunker is ordinarily provided at each end of the car, separated from the lading compartment by respective bulkheads. In accordance with a further aspect of the present invention, circulating mechanism similar to that already described is provided in association with each of the bulkheads; the by-pass passages and the fans for producing by-pass circulation at the respective bulkheads being located preferably adjacent opposite sides of the car. When the cooling air circulation is turned off and only the by-pass circulation is in operation, the pattern of air movement is then particularly suitable for insuring that all parts of the load will be exposed to effective air circulation FIG. 6 illustrates schematically the advantageous circular pattern of air circulation that is produced in the lading compartment by action of by-pass fans 7th and The at opposite ends of the car with that preferred arrangement.

That type of circulation has the particular advantage that appreciable interchange of air takes place between the two ends of the car. A single temperature responsive element placed in the by-pass passage of one bulkhead therefore responds satisfactorily to the average air temperature throughout the lading compartment and may be utilized to control the fans at both ends of the car.

As already indicated, when the air in the lading corn partment requires cooling and the cooling circulation is automatically turned on, it is preferred that the by-pass circulation be maintained also. Maximum possible air flow through the load is thereby maintained during the cooling phase of operation. We have found that heat tends to be exchanged more readily between circulating air and the ice in the ice bunker than between circulating air and the load that is to be cooled. It is therefore desirable during the cooling phase, to provide a greater volume of air flow through the lading compartment than through the ice bunker (or through both ice bunkers when there are two). That is accomplished effectively and economically by the described system.

However, many advantages of the described system may be obtained, in accordance with a further aspect of the invention, by switching the air circulation between the two described types of circulation path, so that cooling circulation takes place only when cooling is required and by-pass circulation takes place only when cooling is not required. That may be accomplished, for example, by disconnecting line 136 from line 134 in the illustrative control circuit of FIG. and connecting it instead to line 162, which receives power from switch contact 143 only when the temperature of element 151 is less than the selected car temperature designated by pointer 154. With that circuit arrangement, the required capacity of power source 136 is somewhat reduced, since the cooling and by-pass fans do not operate simultaneously. With that alternative control arrange ment, temperature sensing unit 154 is preferably placed where it is exposed to air leaving the lading compartment along both the cooling and the by-pass circulation paths. For example, the unit housing may be mounted in a bore in the extreme lower portion of bulkhead stud 44b, projecting on both sides of the stud, as indicated in phantom lines at 165a in FIGURES 2 and 4. Unit is then thermally exposed on one side of the stud to air in passage 41 (FIG. 3) during cooling circulation; and is thermally exposed on the other side of the stud to air in by-pass passage 84 (FIG. 4) during by-pass circulation.

Whereas refrigerator cars and the like are designed primarily for maintaining the temperature of the lading compartment less than the average ambient temperature through which they operate, the ambient temperature is occasionally so low that heat must be supplied within the car to maintain the desired temperature. That may be done by placing a thermostatically controlled heater in one or both of the bunkers, and maintaining air circulation between the bunker and lading compartment. A suitable type of heater is described, for example, in United States Patent 2,717,590, issued on September 13, 1955, and entitled Thermostatically Controlled Wick Type Heater. The present circulation control system is adapted for heating service. For that purpose, temperature selecting arm 154 is set at scale position 2158. Switch arm 141 then remains in the position shown in FIG. 5, engaging contact 142, at all temperatures encountered in practice. Hence both the cooling fans 72 and 74 and by-pass fan 70 operate continuously, insuring efiective air distribution throughout the load. Thermostatic control of the heater unit then provides accurate control of. the temperature at the selected value.

We claim:

1. In combination with a refrigerator car or the like having an ice bunker and a lading compartment separated by a bulkhead, the bulkhead having adjacent its top and bottom edges air passages that communicate between the ice bunker and the lading compartment and form a first circulation path for air between the upper and lower portions of the lading compartment through the bunker; structure forming a second circulation path for air between the upper and lower portions of the lading compartment and by-passing the bunker, sensing means responsive to air temperature within said second circulation path, said sensing means including a control element that is shiftable to one condition when the air temperature is above a predetermined value and is shiftable to a second condition when the air temperature is below that value, fan means actuable to circulate air selectively along said circulation paths, and control means for actuating the fan means in response to the sensing means, said control means acting to cause circulation along the first circulation path only when the control element is in said first condition, and acting to cause circulation along the second circulation path at least when the control element is in said second condition.

2. The combination defined in claim 1 and in which the structure forming the second circulation path includes a vertically extending walled passage isolated by its walls from both the lading compartment and the bunker, communicating at vertically spaced points with the lading compartment, and said sensing means being responsive to the temperature of the air stream flowing in said passage between said points.

3. In combination with a refrigerator car or the like having an ice bunker and a lading compartment separated by a bulkhead, structure forming a generally vertical passageway within the bulkhead and communicating adjacent its upper and lower ends with the lading compartment, the bulkhead having adjacent its top and bottom air edges passages that communicate between the ice bunker g. and the lading compartment and are isolated from said passageway, first circuating means actuable to circulate air between the upper and lower portions of the lading compartment through said air passages and the ice bunker, second circulating means actuable to circulate air between the upper and lower portions of the lading compartment through said passageway, sensing means responsive to air temperature within the car, first control means for actuating said first circulating means under control of the sensing means, and means for actuating the second circulating means at least when the first circulating means is idle.

4. In combination with a refrigerator car or the like having an ice bunker and a lading compartment separated by a bulkhead, structure forming a generally vertical passageway within the bulkhead and communicating adjacent its upper and lower ends with the lading compartment, the bulkhead having adjacent its top and bottom edges air passages that communicate between the ice bunker and the lading compartment and are isolated from said passageway, first circulating means actuable to circulate air between the upper and lower portions of the lading compartment through said air passages and the ice bunker, second circulating means actuable to circulate air between the upper and lower portions of the lading compartment through said passageway, sensing means responsive to air temperature within the passageway, first control means for actuating said first circulating means under control of the sensing means, and means for actu ating the second circulating means at least when the first circulating means is idle.

5. In combination with a refrigerator car or the like having an ice bunker and a lading compartment separated by a bulkhead, the bulkhead having adjacent its top and bottom edges air passages that communicate between t e ice bunker and the lading compartment, first fan means actuable to circulate air between upper and lower portions of the lading compartment through said passages and the ice bunker, second fan means actuable to circulate air between upper and lower portions of the lading compartment via a path that by-passes the ice bunker, sensing means responsive to air temperature within that path, first control means for actuating said first fan means under control of the sensing means, and means for actuating the second fan means independently of the sensing means.

6. The combination defined in claim 5, in which the circulation path that by-passes the ice bunker includes a vertically extending walled passageway isolated by its walls from both the lading compartment and the bunker and communicating at vertically spaced points with the lading compartment, and said sensing means being re= sponsive to the temperature of the air stream flowing in said passageway between said points.

7. In combination with a refrigerator car or the like having an ice bunker and a lading compartment separated by a bulkhead, said bulkhead having an inner face and having a plurality of apertures spaced along the upper edge portion of its inner face, fan means adapted to deliver air streams through the respective apertures in the direction of the lading compartment, and structure forming an air bafile which adjoins the inner face of the bulkhead below the apertures and extends obliquely upward, the upper edge of the bathe being spaced from the car ceiling and forming therewith a passage for air flow into the body of the lading compartment along the car ceiling.

8. In combination with a refrigerator car or the like having an ice bunker and a lading compartment separated by a bulkhead, said bulkhead having an inner face and having a plurality of apertures spaced along the upper edge portion of its inner face, fan means adapted to deliver air streams through the respective apertures in the direction of the lading compartment, structure forming an air baffle which adjoins theinner face of the bulkhead below the apertures and extends obliquely upward, the

upper edge of the baffle being spaced from the car ceiling and forming therewith a passage for air flow between the apertures and the upper portion of the lading compartment, and damper means for at least one of said apertures, said damper means comprising a damper member mounted for swinging movement about a generally horizontal axis parallel to the inner face of the bulkhead and below the lower edge of said one aperture, and means operable to swing the damper member about said axis be tween a closed position substantially parallel with the inner face of the bulkhead and overlying said one aperture and an open position spaced from the inner face of the bulkhead and closely adjacent said air bafiie.

9. In combination with a refrigerator car or the like having an ice bunker and a lading compartment separated by a bulkhead, the bulkhead having air passages that communicate between the ice bunker and the lading compartment, fan means actuable to circulate air through said passages, damper means shiftable between an open position which permits air circulation through said passages and a closed position which prevents that circulation, said damper means being normally biased toward open position, control means actuable to shift the damper means to closed position, sensing means responsive to air temperature within the car, and means controlled in op eration by the sensing means for actuating the fan means when the air temperature exceeds a predetermined value and for actuating the control means when the air ternperature is less than said value.

10. The combination defined in claim 9, also including structure defining a circulation path that includes a verticaliy extending walled passageway isolated by its walls from both the lading compartment and the bunker, and communicating at vertically spaced points with the lading compartment, actuable means for causing circulation of lading compartment air through said passageway, said sensing means being responsive to the temperature of the air stream flowing through said passageway, and said means that is controlled by the sensing means acting also to actuate said last mentioned actuable means at least when said air temperature in said passageway is less than said value.

11. In combination with a refrigerator car or the like having an ice bunker and a lading compartment separated by a bulkhead, said bulkhead having an inner face and an outer face and having a plurality of apertures spaced along the upper edge of its inner face, fan means adapted to deliver air streams through the respective apertures in the direction of the lading compartment, there being an opening in the outer face of the bulkhead communicating between the ice bunker and one of said apertures, structure forming a generally vertical passageway between the inner and outer faces of the bulkhead and communicating adjacent its lower end with the lading compartment and adjacent its upper end with another of said apertures, damper means for controlling air circulation through said one aperture, said damper means including a damper element normally biased toward open position and control means actuable to shift the damper element to closed position, sensing means: responsive'to air temperature within said passageway, and means controlled in operation by the sensing means for actuating the fan means of said one aperture when the air temperature exceeds a predetermined value and for actuating the control means when the air temperature is less than said value.

12. The combination defined in claim 1.1, and including also structure forming an air baffle which adjoins the inner face of the bulkhead below the apertures and extends obliquely upward, the upper edge of the bafiie being spaced from the car ceiling and forming therewith a passage for air flow between the apertures and the upper portion of the lading compartment.

13. The combination defined in claim 13, and wherein the damper element is mounted for swinging movement it about a generally horizontal axis adjacent the lower edge of the baffle, the damper element in open position lying substantially parallel to and closely adjacent the inner face of the battle.

14. In combination with a refrigerator car or the like having an ice bunker and a lading compartment separated by a bulkhead, the bulkhead having adjacent its top and bottom edges air passages that communicate between the ice bunker and the lading compartment, first fan means actuable to circulate air between upper and lower portions of the lading compartment through said passages and the ice bunker, a temperature responsive element mounted in the car, second fan means actuable to circulate a stream of lading compartment air in thermal contact with the temperature responsive element, switch means connected in series with the first fan means, and coupling means between the temperature responsive element and the switch means for closing the switch in response to a temperature exceeding a definite critical value.

15. The combination defined in claim 14, including a walled elongate air passageway isolated by its walls from both the bunker and the lading compartment and communicating at points spaced along its length with the lading compartment, said temperature responsive element being responsive to the temperature of the air stream flowing in said passageway between said points and said second fan means circulating its stream of lading compartment air through said passageway at least when said switch means of the first fan means is open.

16. The combination defined in claim 14, including a walled elongate air passageway isolated by its walls from both the bunker and the lading compartment and communicating at points spaced along its length with the lading compartment, said temperature responsive element being in thermal contact with the air in said passageway between said points and also in thermal contact with the circulation air of said first fan means, and said second fan means circulating its stream of lading compartment air through said passageway at least when said switch means is open.

17. The combination defined in claim 14, and including also means adjustable to vary said critical temperature value and comprising a member manually shiftable among a plurality of alternative positions which correspond to respective alternative critical values of the lading compartment temperature, said positions comprising an eflectively continuous range of positions that correspond to all desired lading compartment temperatures, and an isolated position that corresponds to a temperature spaced below the lowest desired lading compartment temperature, the coupling means, in said isolated position of the member, acting to close the switch effectively independently of the lading compartment temperature.

18. In combination with a refrigerator car or the like having an ice bunker and a lading compartment separated by a bulkhead, the bulkhead having adjacent its top and bottom edges air passages that communicate between the ice bunker and the lading compartment, fan means actuable to circulate air between upper and lower portions of the lading compartment through said passages and the ice bunker, a temperature responsive element mounted in the car in thermal contact with lading compartment air, control means for actuating the fan means under control of the temperature responsive element in response to a temperature exceeding a definite critical value, said control means including a member manually shiftable among a plurality of alternative positions which correspond to respective alternative critical values of the lading compartment temperature, said positions comprising an effectively continuous range of positions that correspond to all desired lading compartment temperatures, and an isolated position that corresponds to a temperature spaced below the lowest desired lading compartment temperature, the control means, in said isolated position of the member, causing actuation of the fan means effectively independently of the lading compartment temperature.

19. In combination with a refrigerator car or the like having an ice bunker and a lading compartment separated by a bulkhead, said bulkhead having an inner face and an outer face and having a plurality of apertures spaced along the upper edge of its inner face, fan means adapted to deliver air streams through the respective apertures in the direction of the lading compartment, there being an opening in the outer face of the bulkhead communicating between the ice bunker and one of said apertures, structure forming a generally vertical passageway between the inner and outer faces of the bulkhead and communicating adjacent its lower end with the lading compartment and adjacent its upper end with another of said apertures, sensing means responsive to air temperature within said passageway, and means controlled in operation by the sensing means for actuating the fan means of said one aperture.

20. In combination with a refrigerator car or the like having an ice bunker and a lading compartment separated by a bulkhead, structure forming a generally vertical passageway within the bulkhead and communicating adjacent its upper and lower ends with the lading compartment, means actuable to circulate air between the upper and lower portions of the lading compartment through said passageway, a temperature responsive element mounted in the bulkhead in thermal contact with air in said passageway, means actuable to control air circulation from the lading compartment through the bunker, and means for actuating the last said means in response to a critical temperature of said temperature responsive element.

21. The combination defined in claim 20 and wherein the last said means includes a control member mounted on the car wall and accessible from outside the car, and mechanical coupling means interconnecting the control member and the temperature responsive element, said control member being manually actuable to vary the value of said critical temperature.

22. In combination with a refrigerator car or the like having an ice bunker and a lading compartment separated by a bulkhead, structure forming a generally vertical passageway within the bulkhead and communicating adjacent its upper and lower ends with the lading compartment, the bulkhead having adjacent its top and bottom edges air passages that communicate between the ice bunker and the lading compartment and are isolated from said passageway, first circulating means actuable to circulate air between the upper and lower portions of the lading compartment through said air passages and the ice bunker, second circulating means actuable to circulate air between the upper and lower portions of the lading compartment through said passageway, said passageway and one of said passages being separated by a common wall, sensing means mounted on said common wall and responsive to air temperatures both in said passageway and in said one passage, and control means for actuating said first circulating means under control of the sensing means.

23. In combination with a refrigerator car or the like having an ice bunker and a lading compartment separated by a bulkhead, the bulkhead having air passages that communicate between the ice bunker and the lading compartment and normally permit gravity circulation of lading compartment air through the bunker to cool the lading compartment, means including a first actuating circuit for producing forced air circulation through said passages to cool the lading compartment, means including a second actuating circuit for preventing air circulation through said passages, sensing means responsive to air temperature within the car, and means controlled in operation by the sensing means for energizing the first actuating circuit when the air temperature exceeds a predetermined value and for energizing the second actuating circuit when the air temperature is less than a predetermined value.

24. The combination defined in claim 23, including a Walled elongate air passageway isolated by its walls from both the lading compartment and the bunker and communicating at points spaced along its length with the lading compartment, and means for producing a circulation of lading compartment air through said passageway at least when the second actuating circuit is energized, and said temperature responsive element being responsive to the temperature of the air stream flowing in said passageway between said points of its communication with the lading compartment.

References Cited in the file of this patent UNITED STATES PATENTS Cooper Mar. 17, 1908 Porges Apr. 14, 1914 Porges Dec. 14, 1915 Huening Feb. 25, 1919 Richardson Jan. 28, 1930 Luhr May 22, 1934 Maginnis Sept. 20, 1398 Dempsey June 4, 1940 Elfving Feb. 9, 1954 Jones Feb. 12, 1957 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N00 3,015,217 January 2 1962 A Paul K. Beemer et a1.

It is hereby certified that error appears in the above numbered pat ent requiring correction and that the said Letters Patent should read as corrected below.

Column 8 line 74, strike out-"air" and insert the same after "'edges'f in line 75,, same column; column 10 line 74 for the claim reference numeral "'13" read l2 column 11 1ine27 after "points" insert a comma.'

Signed and sealed this 12th day of June 1962.

SEAL) Attest:

ERNEST w. SWIDER DAVID LADD Attesting office! i Commissioner of Patents 

